Increasingly, industries rely on a fleet of dispatched mobile units to provide services or deliver products. For example, general contractors, utility providers, cable companies, appliance service providers, truck rental companies, taxi companies, airlines, police/fire departments, and various delivery services all utilize mobile units (e.g., vans, trucks, automobiles, airplanes) as part of their respective operations. When an operation involves numerous mobile units, it is often desirable, yet difficult, to obtain information about the dispatched mobile units. For example, it is desirable to know if a mobile unit has been involved in an accident or if an employee driver is using the mobile unit in an inappropriate manner.
Locating a mobile unit is especially useful if it can be done from a remote management station, such as where the scheduling is done. This remote locating process usually entails two steps: determination of the position of the mobile unit, and transmission of the positioning data or the position data to the remote management station. One of the methods for determining the location of a mobile unit utilizes the Global Positioning System (GPS). The GPS involves a plurality of satellites orbiting the earth and sending out, at synchronized times, a code sequence that identifies the satellite. Along with this identification information is sent some positioning information that can be processed to determine a position. A GPS receiver receives the code sequence and the positioning information and passes it on to a processor. The processor determines the position of the GPS receiver by using well-known methods such as triangulation.
The position information as determined by the GPS receiver is then transmitted to a server that stores all the information. Typically, this transmission from the GPS receiver to the server is achieved via a combination of wireless communication networks such as CDMA and the Internet. FIG. 1, for example, discloses a centralized system 10 whereby a mobile unit 12 with a GPS receiver 14 transmits the positioning information to a remote server 16 via a CDMA network 18. The server 16 stores all the position information in a database 20 and allows client stations 22 to access the database 20 through the Internet 24. Further details of this system are provided in U.S. Pat. No. 5,959,577.
While the system of U.S. Pat. No. 5,959,577 accomplishes the goal of allowing remote management stations to obtain information about mobile units, it has several drawbacks that make the system unappealing to clients. These drawbacks stem primarily from the fact that the position data for all the mobile units 12 are centrally stored at the server 16. There is an inherent lack of privacy associated with this shared-server system, and the possibility that Client A might accidentally access location information pertaining to Client B's fleet may cause enough discomfort on the part of some clients to stop the client from using the system. Furthermore, consolidation of data for all the mobile units in one database poses a scalability problem as more clients join the system, and results in a high maintenance fee. The increased maintenance fee will inevitably get passed on to the clients. Also, if the database experiences a problem (e.g., it crashes), all the clients whose operations depend on the central database will be affected. Lastly, this centralized data control system prevents clients from being able to manipulate the data and report format freely. Whichever format the server 16 uses for its reports, that is the format that is “pushed out” to all the clients. Thus, a client who subscribes to the system of U.S. Pat. No. 5,959,977 could pay a high monthly charge for a system that might not be convenient to use.
A system and method of providing position information to clients in a more cost effective and convenient manner is desired.